Pad bath formulations

In the determination of free formaldehyde in solution, eg, commercial reagents and pad bath formulation, the conditions of analysis allow hydrolysis of the /V-methy1o1 groups, usually between <1% and several percent. The NaOH formed is titrated with hydrochloric acid (82). Because of an incomplete reaction of sulfite with free formaldehyde, these low temperature methods (83) detect only 80—90% of the free formaldehyde present. Skill is important for correct results. 

Pad bath formulations with (a) a highly active catalyst and (b) a conventional catalyst, are shown in Table II. A highly active catalyst may cause low shelf-life of the padding solution. It is, therefore, added last to the formulation to avoid premature polymerization or coagulation of the binder. A strong solution of the mixed catalyst is kept ready and the required quantity of this solution is dispensed through a measuring cylinder and added to the pad bath. 

Ingredients Table II. Pad Bath Formulations With Conventional Catalyst With Highly Active Catalyst ... 

Starch finishes are still used in India. Starch cannot be incorporated into pigment pad-bath formulations since it interferes with the final fastness requirements of pigment dyeings. 

By incorporating polyvinyl acetate and a softener glaze paste into pad-bath formulations, it is possible to combine padding and finishing in one operation to obtain a conventional (nonresin) finish. Compared to starch finishes, this formulation imparts increased fullness, and drape with a soft, silky hand. 

Figure 4-3. A typical chelate structure (Courtesy of Dow Chemical Co.), water and in pectins of cotton. The positively charged metal ions, particularly Fe and Ca are readily available for reaction with any negatively charged anion such as OH or COj and insolubilise soap in the fibre which may disturb subsequent operation. This problem is much more acute when scouring is carried out in continuous process involving padding bath where liquor ratio is much lower than the batch process [5]. Thus, the functions of the chelating agents in the soap and detergent formulations are for the prevention of-...

The emulsion formulations are generally appHed to cloth by padding from a bath and squeezing off the excess. Modifying a formulation in the pad box, eg, to increase or decrease firmness, can be easily done by adding an emulsion or softener. The alkaH-soluble vinyl acetate copolymers previously mentioned can be used as warp sizes during weaving. 

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